ABSTRACT

Mount Popa is a conspicuous dormant volcano, which lies on the volcanic island arc (NS-trending central volcanic line) through the Central Myanmar Basin tectonically. The rheology of lava flows is determined by the phenocryst distribution in the andesitic rocks of Mount Popa, Myanmar. Particularly, the andesitic rock units are differentiated as V1-flow andesite, Nagale-Legyingon plateau andesite, Popa plateau andesite, V3-flow andesite, and V4-flow andesite. The different flow units are megascopic ally very similar in color and texture to porphyritic andesite or augite andesite but different in grain size, and the amount of phenocryst. The phenocryst distribution is graphically correlated with the Newtonian and non-Newtonian flow to interpret the rheology of lava flow during the Pliocene-Holocene eruption of the Mount Popa volcano. A new method which is simplest and practiced to identify the porphyritic andesitic rocks or lava flows not only for the stratigraphy but also the rheology.

KEYWORDS

1. Mount Popa
2. Andesitic lava flow
3. Newtonian and non-Newtonian flow
4. Lava rheology